And it has been an ongoing prank battle ever since, especially while filming the "Oceans" franchise.

2. George Clooney v. Everyone

AP

"My friends are rough on me. Brad Pitt's brutal, and Matt Damon," Clooney told Parade Magazine in 2011. "My friends used to change my outgoing phone message all the time. This was the old days, when you had a phone machine. They would change the message to something horrible and there was nothing I could do to change it back. That was always brilliant."

"I convinced one of my best friends, [actor] Richard Kind, that I was painting. I bought some other pictures, I told him I was studying art. And then for his 40th birthday I gave him this horrible painting. He had to hang it on his wall, [it was by] his best friend! And for years people would come over -- everyone else knew it was out of the trash -- and go, 'That is a beautiful painting.'"

"He was convinced by the end that it was a beautiful painting," Clooney continued. "Until I did 'The Tonight Show' and told the story and then I told him to watch the show. And he said, 'I hate that painting.'"

1. Sarah Silverman and Matt Damon v. Jimmy Kimmel

Back when Sarah Silverman was dating Jimmy Kimmel, the comedian teamed up with Matt Damon to punk her talk show host boyfriend.